I have a large numpy array whNumPylements I individually want to multiply with other indexes and then sum up. My current code is relatively slow, does anyone have an idea how I could make it faster:

```
result = 0
n = 1
int_array = np.array((3,16,3,29,36))
for i in int_array:
result += int(i) * n
n *= 10
```

### >Solution :

In every iteration `10 * prev(10 * ...)`

, So you can use `10 ^ [0, 1, 2, ...] = [1, 10, 100, ...]`

with numpy.array & `numpy.power`

. Then you need `[1*int_arr[0], 10*int_arr[1], ...]`

. At the end, you need `numpy.sum()`

.

```
res = (np.power(10, np.arange(int_array.shape[0])) * int_array).sum()
print(res)
```

Output:

```
389463
```